#Separation Technologies for Sustainable Plant-Based Food Industry

The portfolio of plant-based products in the supermarkets is expanding. In 2018, a study indicated that the plant-based food market is growing at a 10 -old higher rate compared to overall food market growth (Schroeder, 2019). Market share of plant-based products like meat alternatives, vegan foods (milk, cheese, and yoghurt) and nutraceutical compounds has seen steep increase.

Over the centuries, both plant-based and animal-based diets for humans have gone through an evolution to feed the growing population and meet nutritional requirements. The evolution in agriculture resulted in higher productivity and a reduced environmental footprint through the adaptation of modern and smart agricultural practices. On the other hand, evolution of cattle and poultry farming resulted in higher output at the cost of increased nitrogen and methane gas emissions, inefficient utilization of natural resources like water, and protein-rich feedstock from agriculture (cattle feed). Therefore, plant-based foods are still considered to be more sustainable.

The overall sustainability of the agricultural industry depends on the processes involved in converting the harvest to marketable food products. Therefore, it is critical to employ efficient processes to handle plant-based input streams, where complementary choice of feedstock and process technologies defines techno-economic feasibility. In this blog, we provide an overview about how traditional versu highly-selective separation techniques in plant protein purification can influence the outcome with respect to selectivity, operability, scalability, OPEX, and CAPEX. Evaluation basis is:

Selectivity: Degree of freedom to optimize the operating window for high separation efficiency.

Operability: Number of critical process parameters to be monitored and controlled.

Scalability: Number of scale-limiting factors.

OPEX: Raw material, utilities, and energy consumption.

CAPEX: Capital investment and technology lifetime.

Traditional Separation Technologies:

Process Technology

Selectivity

Operability

Scalability

OPEX

CAPEX

Extraction

Good

Average

Good

High

Medium-high

Precipitation

Good

Good

Good

Medium

Medium

Solid-liquid separation

Average

Good

Very good

Medium

Medium

Neutralization

Poor

Very good

Very good

Low

Low

Drying

Poor

Very good

Good

High

High

In the case of the above-mentioned traditional technologies for plant protein purification, selectivity is one of the major concerns because these technologies employ only one separation principle. Even though extraction and precipitation exhibit better selectivity due to the higher degree of freedom to use optimum solvents and precipitating agents, they are often not sufficient enough to handle complex plant-based feed streams with a number of off-flavor compounds and other impurities. Therefore, in this scenario, often the process selectivity becomes a bottleneck to achieve desired product quality.

Separation Technologies with High Selectivity:

Process Technology

Selectivity

Operability

Scalability

OPEX

CAPEX

Adsorption/ Chromatography

Excellent

Good

Excellent

Medium-high

Medium-high

Crystallization

Very Good

Very Good

Good

Medium-high

Medium-high

Hybrid Technologies

Excellent

Good

Average-good

Medium-high

Medium-high

Separation techniques like crystallization, adsorption/chromatography are traditionally known for improved selectivity and hybrid technologies like adsorption-membranes, pervaporation, centrifugal extraction etc. are also used to efficiently address complex separation challenges. Among these technologies, crystallization is an easy technique to operate, while chromatography and hybrid technologies are excellent with respect to selectivity. However, proteins can be sensitive to aggressive process conditions (very high temperatures, etc.) in the case of hybrid technologies and crystallization can be energy-intensive at very large scales. Among the three options, adsorption/chromatography in batch or SMB mode is one of the few techniques operated under close to atmospheric conditions and ideal for both selective removal of off-flavors and protein capture. However, in order to enable its application, robustness and operational efficiency must be improved by reducing buffer consumptions and resin utilization through approaches like continuous processing. This will promote the SMB mode of chromatography operation as a possible solution to enable sustainable processing of plant-based feedstock.